Wilcoxon's t-test

Today we covered the last statistical test - Wilcoxon's. This is used when the investigation has a repeated measures or matched pairs design. The worksheets to fill in are here and here and the ppt is here.

Here is a useful summary of all four statistical tests.

Here is a useful overview of the different types of data (nominal, ordinal etc). 

More statistics

Today we covered two more statistical tests - Mann-Whitney and Chi-squared. You need to know when to use each test and how to complete each test, although you would never be asked to complete a whole test. The formulae and necessary tables will always be available on the exam paper as well.

Tomorrow we will do Wilcoxon and then look at the exam questions on statistical tests.

The Mann-Whitney worksheets are here and here. The Chi-squared tests are here and here.

Probability and significance

Today we started the statistics section of the research method spec with a look at probability and significance (ppt here). Remember we always start off with a null hypothesis, with the aim being to try and disprove this and find something significant. If the probability of getting our results when the null hypothesis is true, is less than or equal to 0.05 then we say we have a significant finding and our null hypothesis can be rejected.

We then looked at our first statistical test, Spearman's rho. This is used when the data is from a correlation and when the data is ordinal or nominal. The ppt is here and the worksheets to fill in and work through are here and here. 

June 2014 papers and mark schemes

The June 2014 question paper and mark scheme are not on the AQA website. The links are as follows for you to download:

Unit 3 paper
Unit 3 mark scheme
Unit 4 paper
Unit 4 mark scheme

More research methods

Today we covered quite a lot of material from the RM section of unit 4. A lot of this is revision from AS, and is all fairly straighforward. You need to make sure you that a) you use the correct terminology and b) you answer the exam questions in the context that they are are set - so if the question is about patient health questionnaires then refer to these in your answer.

The ppt on reliability is here and the writing frame is here.

The ppt on validity is here and the writing frame is here.

The ppt on sampling techniques is here and the one on descriptive statistics (measures of dispersion, spread and graphs) is here.

Make sure you complete the following questions as homework:

June 14 Q18

June 13 Q20, Q22

January 13 Q17, Q20

Research Methods

Here is the schedule explaining what we will be doing every lesson this term. We will be covering the research methods section of the unit 4 paper.

Yesterday we spent some time revising our knowledge of the different research methods from AS. The ppt is here and the big table to fill in is here. We also discussed research design - independent groups, matched pairs and repeated measures. The ppt for this material is here, but this is well covered in any AS textbook.

Today (Wednesday) we looked at the Scientific process and peer review (ppt here) . This is all fairly straightforward and easy marks if you know the material.

AO2 points for essays

Reigner has helpfully come up with a really useful list of all the possible AO2/AO3 points that could be useful to comment on in an essay:

- Weakness + how it impacts study

- Strengths + how it impacts study

- Alternative Explanation

- Generalisability

- Ethics

- Ecological/Temporal/External/Internal Validity

- Correlation, corr. doesn't equal causation

- Cause and Effect

- Gender Bias

- Deterministic/Simplistic

- Reductionist

- Experimenter/Participant Bias

- Individual Differences

- Sample Size

- Diathesis Stress Model

Here are three more from me:

Population bias (most psychology expts are carried out on psychology undergraduates)
Animal research - evaluate in terms of generalisability and ethics
Evaluate the research design (independent groups/repeated measures etc) and say whether this was a good or bad choice of design & why

Thanks Reigner